How is the iframe name attribute determined?

Where do I find, and possibly change, how fancybox is generating the name attribute in the iframe tag?

I’ve “heard” that there is a work-around to making social site popups for sharing your blog posts actually work in iframes, but it involves being able to address the iframe name, which in this case is ‘fancybox-frame[bunch of random numbers]’. And of course everytime the page is loaded those bunches of numbers are different.

Is there a way to change the output of the name and if so where? I’ve searched through the plugin files but nothing is coming up obvious for me. 🙂